The U.S. Secret Service failed to replace a broken alarm system at the Houston home of former President George H.W. Bush for more than a year, according to a government report on the troubled protection agency.

The report, sent to Secret Service Director Joseph Clancy and released on Thursday, was compiled by the Department of Homeland Security's inspector general, John Roth, who said the agency will improve its process for tracking maintenance problems with security equipment and keeping it up to date.

The 20-year-old alarm system at Bush's home stopped working in September 2013 and was not replaced until November or December 2014. The report said the agency had been warned about the alarm in 2010 but a request to have it replaced was rejected.

The DHS said a Secret Service employee was assigned to patrol the property while the system was broken and no security problems occurred.

The report said similar vulnerabilities could affect residences of other former presidents.

Bush said on Twitter that he and his wife, Barbara, "have great respect for, and confidence in, the men and women of @SecretService. That respect and confidence has never waned."

Roth's report is part of an overview of security breaches. A man with a knife jumped the fence and entered the White House last year and another man fired shots at the presidential residence in 2011.

Roth's office is also investigating incidents in which Secret Service supervisors drove a government vehicle into an investigation scene at the White House after a party and allegations of sexual assault and improper use of the agency's data base by employees.

Julia Pierson resigned as director of the Secret Service in October, a few weeks after the White House intruder incident.

The agency's credibility also has been tarnished by agents who hired prostitutes while on assignment in Colombia in 2012.

Republican Representative Jason Chaffetz, chairman of the House's oversight committee, and Elijah Cummings, the committee's ranking Democrat, said it was "startling and unacceptable" for the Bush residence to be without an alarm for so long.

"This adds to the growing list of significant concerns Congress has had with the management of the Secret Service," they said in a statement.